Date: Sun, 20 Jul 2008 04:00:22 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: "Alexandre \"Sunny\" Kovalenko" <gaijin.k@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: Broken APIC on my laptop or bug in FreeBSD? Message-ID: <874p6lfjyx.fsf@kobe.laptop> In-Reply-To: <1216514182.2172.28.camel@RabbitsDen> (Alexandre Kovalenko's message of "Sat, 19 Jul 2008 20:36:22 -0400") References: <87prpcjrsk.fsf@kobe.laptop> <1216501388.971.6.camel@RabbitsDen> <87mykd5wsl.fsf@kobe.laptop> <87tzelebd7.fsf@kobe.laptop> <1216508230.2172.8.camel@RabbitsDen> <87iqv1h1g8.fsf@kobe.laptop> <1216514182.2172.28.camel@RabbitsDen>
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On Sat, 19 Jul 2008 20:36:22 -0400, "Alexandre \"Sunny\" Kovalenko" <gaijin.k@gmail.com> wrote:
> What I meant is that my laptop, runnig RELENG_7 is pretty happy with
> "C2" (set through /etc/rc.conf as performance_cx_lowest="C2", and even
> "C3" (set through /etc/sysctl.conf as dev.cpu.1.cx_lowest=C3), so long
> as cpu0 is not allowed to go into C3. You seemed to indicate that in
> your case nothing but "C1" worked. If you just did not try the
> configuration above, would you, please, try it and see if it works.
> Apart from, hopefully, giving someone the data point, it will make
> your laptop cooler and less power hungry.
Ah, now I get it :)
Well, I did try the following after booting with both CPUs in C1 state:
(1) hw.acpi.cpu.cx_lowest: C1
dev.cpu.0.cx_lowest: C1
dev.cpu.0.cx_lowest: C2
I left the laptop to boot with both CPUs in C1, and then after a
while I manually set dev.cpu.0.cx_lowest=C2. This setup seems
ok. I can see processes being scheduled on both cpu.0 and cpu.1
and there's no "freeze" when the laptop is idle.
(2) hw.acpi.cpu.cx_lowest: C1
dev.cpu.0.cx_lowest: C1
dev.cpu.0.cx_lowest: C3
Same as above, only this time I set dev.cpu.0.cx_lowest=C3.
(3) hw.acpi.cpu.cx_lowest: C1
dev.cpu.0.cx_lowest: C2
dev.cpu.0.cx_lowest: C2
Not ok. When the laptop stays idle for some time, it starts
getting too slow to type stuff in a terminal, and after a while
I get `calcru: runtime went backwards' messages.
I don't know if being scheduled on cpu.1 when it is in C2/C3 state has
any measurable impact on user processes. Should I leave the settings to
option (1) or (2) above for a while? Is there any way to find out if
this causes any problems?
Right now I am running for a couple of minutes with
$ sysctl -a | fgrep .cx_
hw.acpi.cpu.cx_lowest: C1
dev.cpu.0.cx_supported: C1/1 C2/1 C3/57
dev.cpu.0.cx_lowest: C1
dev.cpu.0.cx_usage: 100.00% 0.00% 0.00%
dev.cpu.1.cx_supported: C1/1 C2/1 C3/57
dev.cpu.1.cx_lowest: C2
dev.cpu.1.cx_usage: 0.00% 100.00% 0.00%
and things seem ok so far :-)
Thank you for all the help. It's been _very_ useful :)
> Few more data points:
> -- CPU0 and CPU1 are somehow not treated interchangeably by FreeBSD.
> -- at some point when earth was warm and 7.0 was CURRENT, "C3" used to
> work on my laptop, even on CPU0.
> -- I have not filed a PR. If you think it is warranted, you could do it
> or I can -- it's just I did a couple of embarrassing ones and got
> somewhat trigger-shy ;)
Heh. I've filed my own share of bogus PRs too. Please don't feel shy,
and just report whatever seems out of the ordinary. It's better to have
a few extra PRs that are not really bugs, than never-fixed bugs :)
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